Screening and comminuting device



Jan. 22, 1963 s. P. RUDZINSKI 3,074,555

SCREENING AND COMMINUTING DEVICE Filed Dec. 29, 1959 3 Sheets-Sheet 1 Luge Lt Jan. 22, 1963 Filed Dec. 29, 1959 3 Sheets-Sheet 2 on w l7 1 m a m e 9 S w I w lvujazim 3,074,555 SQREEIJEIG AND tII-JMMENUTING DEVICE taniey P, Rudzinski, 11% S. Lombard Ava, Oats Park, lil. Filed Dec. 29, 1959, Ser. No. 362,649 7 Claims. (Cl. 216-452) The present invention relates to a device for screening and comminuting or cutting solids and foreign matter in a stream of fluid material such as found, for example, in the fluid in sewage treatment plants and in water used in irrigation and drainage systems.

it is a general object of the present invention to simplify the installation of such a screening and comminuting device and at the same time maintain high efficiency of operation.

Another object of the present invention is to provide a screening and comminuting mechanism which is self-contained and permits installation in a straight channel or fluid passage.

A related object is to provide a large screening surface for a given size of channel to promote free fluid flow by reduced resistance to fluid flow.

It is a further object of the present invention to provide a screening and comminuting mechanism with improved cutting action and low cost maintenance of the cutters. A more detailed object is to provide a mechanism in which relative movement between the cutting members is reversible for more efficient comminuting of the solids and foreign matter in the fluid.

Other objects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevation partly in section illustrating a preferred construction of a screen and comminuting device embodying the present invention;

FIG. 2 is a front elevation of the device of FIG. 1 looking downstream in the direction of fluid flow;

PEG. 3 is a section on an enlarged scale taken along the section line 33 of FIG. 1 illustrating the cutters for comminuting or shredding solids;

FIG. 4 and FIG. 5 are perspectives showing the form of the cutters on the rotor and cutter bar, respectively;

FIG. 6 is a side elevation partly in section illustrating an alternative form of mechanism embodying the invention.

Referring now to the drawings in more detail, there is illustrating a screening and comminuting mechanism 19 adapted for placement in a channel or pipe 11 of concrete or other fiuid retaining material. As there shown, the mechanism comprises a rotor screen 12 and a stationary cutter bar 14, the rotor being driven by a suitable source of power such as an electric motor 15.

In accordance with the present invention, the rotor 12 and cutter bar 14 are arranged and constructed to permit continuous flow of the fluid with alined inlet and outlet openings. Such construction greatly simplifies the installation and maintenance of the eomrninutor as well as increasing efficiency of operation over comminutors heretofore available.

For this purpose the screen and comminutor mechanism has a casing 16 preferably of cylindrical shape, which serves both to support the device as a unitary structure and to channel fluid through the screen. Preferably the casing is formed by upper and lower semicylindrical sections 17, 18 for ease of assembly and maintenance. Suitable lugs or bosses 19, 2d are provided for receiving bolts 21 to hold the two sections together. The lower portion of the casing may if desired have a base portion 22 having a flat, rectangular bottom surface and an upper curved Etates Fascist lice surface corresponding to the curvature of the casing. In the illustrative embodiment of the invention, the base portion is integral with the lower section of the casing.

Positioned concentrically and coaxially within the casing 16 is the rotor 12 which both screens out solids in the fluid flow and also aids in comminuting solids in the fluid. In the construction of FIGS. 1 and 2, the rotor 12 has a generally conical shape with the apex of the cone pointed in an upstream direction. The direction of flow is indicated by a large arrow in FIG. 1. It is intended, and is to be understood, that other shapes than a cone may be used for the rotor. In general, any surface of revolution which is closed in the center and radiates outwardly therefrom is contemplated and suitable for the rotor. A cone or other bulbous shape, such as an oblate or prolate spheroid or a portion thereof, is preferred over a flat circular rotor for the reason that greater area of cutting and screening is provided by the bulbous shapes.

In the preferred embodiment of the invention of the drawings, the rotor 12 is formed by a series of circular bars or rings 24 of gradually increasing diameter, the smallest ring being at the apex of the rotor and the largest at the base. The bars or rings 24 are suitably spaced from each other to form a conical surface of revolution having openings to permit fluid to flow through the rotor. The bars 24 are sufliciently close together to provide openings which will hold back and retain solid particles larger than a predetermined size. interconnecting and supporting the bars or rings 24 in proper spaced and coaxial relationship are four equally spaced ribs 25 which extend outwardly and rearwardly from the apex of the rotor 12. Mounting the rotor 12. for rotation is a sleeve 27 to which are attached to the inner ends of the ribs such that a unitary structure is provided.

In the manufacture of the rotor 12 the entire unit may be made as an integral casting having a central sleeve 27, radiating ribs or spokes 25, and a conical outer shell. Circular slots 23 may then be machined in the shell to form the individual spaced bars or rings 24 integrally connected to the ribs 25.

Flow of fluid through the rotor herein described is not, as might be expected, a straight line flow. On the contrary, the flow is curved or bent inwardly as it passes through the opening or slot between adjacent rings or bars 24. In the illustrative embodiment of FIG. 1 of the drawings this curvature or bending is increased by the overlapping of the outer edge portion of one ring and the inner end portion of the next larger or downstream ring. Aside from such overlapping, rotation and the overall shape of the rotor cause similar inward bending of the stream flow in the region of the slots. Such curvature and bending is advantageous in causing slender solid particles, such as threads, strings and the like, to be trapped on the screen where they may be subjected to comminuting action.

For supporting the rotor there is provided a shaft 2% concentric with the casing and rotatably mounted on the casing at its forward and trailing ends. In this connection the cutter bar 14 serves the dual function of holding stationary cutters 32 and of carrying a bearing 33 for the forward end of the rotor shaft 2%. As shown in FIGS. 1 and 2 of the drawings, the cutter bar is bolted or otherwise fastened to the lower section 18 of the casing 16 and has an upper surface which slopes upwardly and forwardly from the lower rear center of the casing. The outline of the upper surface of the cutter bar 14 conforms to the profile shape of the rotor face and is in close proximity to the lower side of the latter. A suitable web S or other bracing is provided on the cutter bar so that it will have sufficient strength and rigidity to snrasse in the exemplary construction by the upper half of the casing 17 through a tubular drive shaft housing 35. ,To

provide a unitary structure, the drive motor 15 for the rotor 12 is mounted on a horizontal bracket 37 fastened to the center rear portion of the upper section 17 of the. casing. Such location for the motor 15 elevates it above, and keeps it out of, the fluid flowing through the screen and comminutor. As seen in the, drawings, the. motor 15 is mounted in a vertical manner with the motor drive. shaft at; extending downwardly at the rear of the casing. A pair of bevel gears 42 interconnect the drive shaft, and the rotor shaft to provide a right angle drive for the rotor. V

Surrounding the motor drive shaft ll; and supported by the motor bracket 37 is the watertight tubular housing 36. Fastened to the lower end of the housing 36 is a right angle casting 44 which encloses, the bevel gears and at its forward end has a bearing 45 for rotatably supporting the rear portion of the rotor shaft 29. A removable plate as on the casting permits the assembly and inspection of the bevel gearing.

if additional support for the drive motor 15 and rear bearing 45 of the rotor shaft 29 is desired, a vertical support therefor can be mounted on the rear portion of base 22.

The comminuting of solids is accomplished in accordance with the present invention by a cutter mechanism which is operated by relative rotation of the rotor 12 and the cutter bar 1-?- each of which is provided with a series of teeth or cutters d8, 32. With reference to FIGS. 4 and 5, there is illustrated the preferred form of cutters especially adapted for periodically reversing the direc tion of rotation of the rotor to give increased efficiency of cutting.

The rotor cutters 48 are formed on short rectangular bases 4-9 of sufficient length to bridge two adjacent bars or rings 24 on the rotor 12. The rotor bars are preferably recessed or notched on their outer surface to receive the bases 4-9 of the cutters. Suitable mounting holes 51 adjacent the ends of the bases 49 are provided for receiving screws 52. or other fasteners to hold the bases to the rotor bars. Centrally of each base and extending transversely thereof is a rectangular projection forming a cutting tooth 53.

Positioned on the upper edge of the cutter bar 14- adjacent to and extending along a segment of the rotor surface are a series of stationary cutters 32 placed end to end to form a continuous cutting edge. Each of the individual cutters is a flat plate 56 whose longitudinal edges form cutting edges. These edges 56 are notched, as at 57, to conform to the shape of the cutting teeth 53 mounted on the rotor. In this manner the cutting action takes place along the entire leading edges 56, 59 of the stationary and rotor cutters, including the end and sides of the teeth 53 and notches $7. In order to obtain full use of the leading corner edge 59 on the rotor cutters 48, the recesses in the rotor bars 24 which receive the cutters 48 may be slightly shallower than the base 49 of the cutter 48 thus allowing the edge 59 to coact with the corresponding cutting edge 55 on the stationary cutter 2-2.

Quick and simple replacement of all cutters is permitted by the described construction. As previously indicated, the rotor cutters 48 are accurately positioned by recesses in the rotor bars 24 and easily attached and detached by screws or similar fasteners. The stationary cutters 32 are likewise easily replaced by the use of mounting holes 61 and screws 62 or other fasteners. In addition, the stationary cutters 32 are constructed for top to bottom inversion such that the bottom cutting edge 63 may be used when top edge 56 becomes worn. This-is accomplished by locating the mounting holes at centrally of the cutter body and forming the bottom edge 63 with notches 57 identical to those in the top cutting edge 5-5.

As shown in the drawings with particular reference to FIG. 2, the rotor cutters 48 may be arranged on the rotor in various ways. Preferably, the rotor cutters 48 are in staggered arrangement, such as a plurality of sets of cutters, each set being positioned along a curved line, spiralling outwardly from the anex or central portion of the rotor to the periphery portion.

In the embodiment shown in the drawings the cutters 32 on the stationary cutter bar 14 are inclined slightly with respect to the face of the cutter 48 on the rotor 12. This inclination is not critical and may be more or less as desired. An angle of 69 to 70 degrees is suggested for efficient cutting without clogging, on the one hand, or outward movement of the foreign matter away from the cutters, on the other. It is, for example, contemplated within the scope of the present invention that the rotor 12 may be rotated in one direction for a given number of revolutions, and then the direction reversed. For such operation the cutters 32 on the cutter bar 14 may be set with no inclination, that is, in radial alinement with. the rotor. The cutters then present approximatcly the same cutting angle for both directions of rotation. Preferably, however, a second set of stationary cutters could. be placed on the opposite side 64 of the cutter bar 14. I I V 7 In connection with cutting by means of reversing the rotation of the rotor, a pair of cutting bars 14 may be used. The cutter bars would preferably extend downwardly from the axis of rotation to. the casing 16 and be spread from each other by a suitable angle of say 60 degrees. Each bar would have a suitable series of cutters 32 on its upper edge on the side facing away from the other cutter bar.

In FIG. 6 of the drawings, an alternative embodiment of the invention is illustrated. In this instance, a conical rotor 112 is positioned with the apex pointed in the downstream direction and with the inner surface of the rotor facing upstream. In this form, spaced bars or rings 124 are provided on the inner conical surface and a plurality of supporting ribs 125 on the outer surface. Since solids in the fluid stream are interceptedand retained on the inner surface of the rotor 112,2. cutter bar 114, fastened by bolts or the like at its forward end to a suitable supporting base or casing 116, slopes rearwardly, along a segment of the rotor 112 on the upstream, inner surface. Stationary cutters 132 and movable cutters 14d of the form previously described are fastened respectively to the inside of the rotor 112- and the adjacent edge of the cutterbar 11d.

As, in the prior embodiment, the, alternative form of rotor 112 isdriven by an electric. motor which preferably is supported onthe casing 116 above the level. of the fluid. A depending drive shaft and suitable right angle gearing, enclosed by a tubular support housing 136 interconnects the rotor 112 and drive motor 115. The rotor 112. is supported by the horizontal section of the drive shaft which is journaled in a first bearing 133 on the rearward end of the, cutter bar 114 and a second bearing 1 .5 in the lower end of the support housing 136.

It. will beapparent that the screening and cornminuting device of the present invention is thus capableof considerable flexibility to different conditions and applications, while at the same time being of low cost construction and installation. As shown in FIGS. land 2, the fluid channel or conduit requires no complicated elbows or turns to accommodate the described mechanism, but on the contrary may be a simple straight channel. In the cylindrical conduit or pipe 11 in FIGS. 1 and 2, the device of the invention may be simply substituted for a corresponding length of conduit or pipe. In an open channel, the casings 16, file, may, for example, be fitted with suitable lateral shields having anexternal outline conforming to the cross section of any channel in which the mechanism may wish to be used. Furthermore, screens and comminuting mechanisms embodying the present invention may be of various sizes to accommodate different installations and may have rotors of differing configurations to accommodate the desired rate of fluid flow, as previously described.

I claim as my invention:

1. A screening and comminuting mechanism comprising, in combination, a cylindrical casing for the flow of fluid lon itudinally therethrough, a series of circular bars, the circles formed by said bars being of sequentially increasing diameter in an axial direction and arranged to define a surface of revolution within said casing and coaxial therewith, said bars being spaced from each other a distance to screen solids from fluid flowing therethrough, means for supporting said screen bars for unison rotation about the axis of said casing, including a stationary cutter bar, said screen bars having fixed thereto a plurality of cutters each having cutting edges, said cutter bar having a series of alined cutting edges thereon positioned to extend along the upstream surface of said screen bars, and conforming in outline to the cutting edges on said cutters for coaction therewith, and drive means for rotating said screen bars and cutters to cut solids screened from the fluid by said screen bars.

2. The screening and comminuting mechanism defined in claim 1 in which each of said circular bars is offset axially from the preceding bar to form a substantially conical surface,

3, A screen and cutting mechanism for use in a flow of fluid comprising, in combination, a series of circular bars, the circles formed by said bars being of successively increasing diameter in an axial direction and on a common axis to define a surface of revolution, said axis extending in the direction of fluid fiow, said bars being spaced from each other a predetermined distance to form a screen for retaining solids on the upstream side thereof, means for supporting said screen bars for unison rotation about said axis, said screen bars having a plurality of cutters fixed thereto on said upstream side, a series of cutting edges positioned adjacent said upstream side of said screen bars, and shaped to correspond in outline to said cutters on said screen bars for coaction therewith, and drive means for rotating said screen bars and cutting edges relative to each other for cutting solids screened from the fluid by said screen bars to a size which will pass through said screen.

4. The screen and comminuting mechanism defined in claim 3 in which each bar is offset axially from the preceding bar by a distance greater than the axial width of the latter and the outer diameter of each bar is greater than the inner diameter of the next larger bar for causing the flow of fluid to bend as it passes between said bars.

5. A mechanism for screening and comminuting solids in a flow of fluid comprising, in combination, a cylindrical casing having alined inlet and outlet openings for axial flow of fluid therethrough, a rotor within said casing having a series of circular members of successively increasing diameter arranged to define a surface of revolution facing upstream of the fluid flow, the axis of revolution of said surface and the axis of said rotor being coaxial with said cylindrical casing, the adjacent edges of adjacent ones of said members being spaced from each other to form screening openings for retaining solids on said surface of revolution and permitting fiuid to flow through said surface, first means for supporting said rotor for rotation on the axis of said casing, including a first bearing and a stationary cutter bar mounted on said casing and extending to the axis thereof along the upward said rotor cutters and shaped to conform to the outline of the latter for cutting coaction therewith, drive means including a drive motor supported on and above said casing and a depending drive shaft for rotating said rotor for comminuting solids retained on said screening surface, and a second means for supporting said rotor including a housing surrounding said drive shaft and a second bearing mounted thereon.

6. A screening and comminuting device for use in a fluid flow comprising, in corn ination, a series of coaxial circular screen bars, the circles found by said bars being of progressively increasing diameter in an axial direction and arranged to define a surface of revolution, said bars being spaced from each other a distance to define openings in said surface for screening solids from fluid flowing therethrough, the outer diameter of each bar being slightly greater than the inner diameter of the next larger bar for causing the flow of fluid to bend as it passes between said bars, a cylindrical casing having alined inlet and outlet openings and enclosing said series of screen bars for channeling fluid flow therethrough, said casing extending beyond both sides of said surface, means for supporting said screen bars for unison rotation about the of said casing, including a shaft, an upwardly extending cutter bar and a journal on said bar supporting the forward end of said shaft, said screen bars having a plurality of cutters fixed thereto, said cutters having a cutting edge facing in the direction of rotation of said rotor, said outter bar having a series of stationary cutting edges located adjacent the upstream surface of said screen bars and conforming in outline to the cutting edges on said cutters for coaction therewith, and drive means for rotating said screen bars and cutters to cut solids screened from the fluid by said screen bars, said drive means being mounted on an upper portion of said casing and including a depending drive shaft, a bearing support for the rear portion of said rotor shaft, and right angle gearing interconnecting said shafts so that said device forms a unitary structure adapted to constitute a section of conduit.

7. A screening and cutting mechanism for use in a flow of fluid comprising, in combination, a driven rotor mounted for rotation and having a series of spaced circular members defining a plurality of slots therebetween for screening out and retaining solids on the upstream side of said members, cutters on said rotor, each having a body spanning one of said slots with the end portions thereof overlying adjacent circular members, said adjacent members having alined recesses for receiving and positioning said respective end portions on said body midway between said end portions, said body having fastening means in the end portions thereof and a cutting tooth positioned symmetrically between said fastening means and extending transversely of said body, said body and cutting tooth having cutting edges on both sides thereof to permit end-for-end reversal of said body in said recesses to present either cutting edge toward the direction of rotation of said rotor, a stationary cutter bar extending along the side of said rotor and having a plurality of flat, rectangular cutter plates mounted thereon with the major sides of said plates extending generally radially of said rotor, each of said stationary cutters having its two opposed minor sides shaped to correspond to the cutting edges of said rotor cutter, said cutter plates having fastening means on the long axis of said plates to present either of said minor sides toward said rotor for coaction with the cutters thereon.

References Qited in the file of this patent UNITED STATES PATENTS 2,085,326 Nordell June 29, 1937 2,295,633 Chase Sept. 15, 1942 2,305,935 Thom Dec. 22, 1942 2,477,096 Silcox July 26, 1949 

7. A SCREENING AND CUTTING MECHANISM FOR USE IN A FLOW OF FLUID COMPRISING, IN COMBINATION, A DRIVEN ROTOR MOUNTED FOR ROTATION AND HAVING A SERIES OF SPACED CIRCULAR MEMBERS DEFINING A PLURALITY OF SLOTS THEREBETWEEN FOR SCREENING OUT AND RETAINING SOLIDS ON THE UPSTREAM SIDE OF SAID MEMBERS, CUTTERS ON SAID ROTOR, EACH HAVING A BODY SPANNING ONE OF SAID SLOTS WITH THE END PORTIONS THEREOF OVERLYING ADJACENT CIRCULAR MEMBERS, SAID ADJACENT MEMBERS HAVING ALINED RECESSES FOR RECEIVING AND POSITIONING SAID RESPECTIVE END PORTIONS ON SAID BODY MIDWAY BETWEEN SAID END PORTIONS, SAID BODY HAVING FASTENING MEANS IN THE END PORTIONS THEREOF AND A CUTTING TOOTH POSITIONED SYMMETRICALLY BETWEEN SAID FASTENING MEANS AND EXTENDING TRANSVERSELY OF SAID BODY, SAID BODY AN CUTTING TOOTH HAVING CUTTING EDGES ON BOTH SIDES THEREOF TO PERMIT END-FOR-END REVERSAL OF SAID BODY IN SAID RECESSES TO PRESENT EITHER CUTTING EDGE TOWARD THE DIRECTION 